Fabrication of antioxidative and antibacterial surface coatings with metformin-loaded self-assembled multilayers for periodontal regeneration in diabetes mellitus patients

Rescuing the compromised function of periodontal ligament stem cells (PDLSCs) due to hyperglycemia-induced oxidative stress and reducing the risk of postoperative infection around the interface of scaffold materials are of prime importance for periodontal regeneration in diabetes mellitus. To this end, a facile and green approach for the establishment of surfaces with antioxidative and antibacterial properties was developed in this work. Briefly, the surfaces of polystyrene (PS) plate were pre-modified with polydopamine and then coated with a genipin crosslinked layer-by-layer (LbL) assembly, which was established by using the antibacterial polyelectrolytes carboxymethyl chitosan (CMC) and polylysine (PLL) as building block. Metformin as an antioxidative agent was incorporated into the discrete nanolayers to achieve sustainable release. Our research showed that metformin-loaded LbL assembly presented favorable cytocompatibility. The released metformin could partially rescue the impaired osteogenic function of human PDLSCs induced by high glucose in vitro. Meanwhile, owing to the antibacterial activity of CMC and PLL, the colonization of common pathogenic bacteria related to periodontal disease could be disturbed on the surface of developed coatings. Accordingly, the presented strategy for surface functionalization of materials in our study holds a promising potential for periodontal regeneration application in diabetic patients.